Paint hose extension for electrostatic spray gun

Abstract

A paint hose extension to facilitate safe application of metallic paints with a hand held electrostatic spray gun. The hose extension extends between the spray gun and a hose connected to a grounded paint supply. The hose extension provides a predetermined long electrically insulated paint flow path between a high voltage paint charging electrode in the spray gun and the paint supply hose. An electrically conductive layer shields the hose between an electrically grounded handle on the spray gun and a remote metallic connector which attaches to the paint supply hose. The connector electrically connects the conductive layer with the grounded paint column at the connector.

We claim: 
     
       1. A paint hose extension for insertion between a free end of a paint supply hose and an electrostatic paint spray gun having an electrically grounded handle, a barrel and nozzle assembly for receiving and atomizing paint and a high voltage electrode for imparting an electrostatic charge to the paint, said paint supply hose having a remote end connected to an electrically grounded paint section, said hose extension comprising electrically non-conductive hose means extending between said barrel and nozzle assembly and said paint supply hose for providing a predetermined long electrically insulated paint flow path between said paint supply hose and said barrel and nozzle assembly, means supporting said hose means at said spray gun from said handle, an electrically conductive layer surrounding said hose means between said support means and said paint supply hose, means electrically connecting said conductive layer to said spray gun handle, and means electrically connecting said conductive layer to paint at said free end of said paint supply hose whereby paint in said supply hose is electrically grounded at both ends of aid supply hose. 
     
     
       2. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 1, wherein said means electrically connecting said conductive layer to paint in said paint supply hose comprises metallic connector means for connecting said hose means to said paint supply hose, said connector means electrically contacting said conductive layer and electrically contacting paint flowing from said paint supply hose to said hose means. 
     
     
       3. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 1, wherein said hose means includes a polyethylene core tube, and wherein said conductive layer comprises a layer of conductive nylon. 
     
     
       4. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 3, wherein said conductive layer has a resistance no greater than 5,000 ohms per foot along said hose means. 
     
     
       5. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 3, wherein said hose means further includes a polyurethane sheath covering said core tube and said conductive layer between said support means and said paint supply hose. 
     
     
       6. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 1, wherein said conductive layer has a resistance no greater than 5,000 ohms per foot along said hose means. 
     
     
       7. A paint hose extension for connecting a paint supply hose to an electrostatic paint spray gun, as set forth in claim 1, and further including an electrically insulating tube surrounding said hose means between said supporting means and said barrel and nozzle assembly.